Gastric residence systems (GRS) are delivery systems which remain in the stomach for extended periods of time. They enable oral delivery of an active pharmaceutical ingredient (API), diagnostic or electronic device etc. to the gastrointestinal (GI) tract, for example for the purpose of extended GI residence, for local treatment of the upper GI, for continuous exposure of drugs especially those with a narrow absorption window or low solubility in the intestine. Gastric residence systems fall within three areas of technology: namely floating systems, bio-adhesives and systems with expanding geometry through swelling or unfolding.
Folding systems are conveniently administered to a patient in a folded or compacted form for example via a capsule. Once in the stomach, dissolution of the capsule in the stomach results in the system expanding or unfolding to a size which resists passage through the pyloric sphincter over the desired residence period. Examples of such systems are described in the following publications: U.S. Pat. No. 4,735,804, PCT/US2015/033850, PCT/US2015/035423, PCT/IB2011/002888.
Requirements for effective folding systems include providing a safe and pharmaceutically acceptable system which is compact for swallowing, unfold to effective expanded systems that can endure the mechanically and chemically harsh environment of the stomach for a desired residence period and eventually exit the stomach safely and in a timely manner. The present disclosure describes advancements in the design of improved structures for extended residence in the stomach.